Mary Ainsworth

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John Bowlby (1969) believed that attachment was an all or nothing process. However, research has shown that there are individual differences in attachment quality.

Indeed one of the primary paradigms in attachment theory is that of the security of an individual’s attachment (Ainsworth 1970, 1978).

Much research in psychology has focused on how forms of attachment differ between infants. For example, Schaffer and Emerson (1964) discovered what appeared to be innate differences in sociability in babies; some babies preferred cuddling more than others, from very early on, before much interaction had occurred to cause such differences.

However, it was probably the psychologist Mary Ainsworth (1913 - 1999) who provided the most famous body of research offering explanations of individual differences in attachment.

It’s easy enough to know when you are attached to someone because you know how you feel when you are apart from that person, and, being an adult, you can put your feelings into words and describe how it feels.

However, most attachment research is carried out using infants and young children, so psychologists have to devise subtle ways of researching attachment styles, usually involving the observational method.

Psychologist Mary Ainsworth devised an assessment technique called the Strange Situation Classification (SSC) in order to investigate how attachments might vary between children.

The Strange Situation was devised by Ainsworth & Wittig (1969) and was based on Ainsworth’s previous Uganda (1967) and later Baltimore studies (Ainsworth et al., 1971, 1978).

The Ainsworth and Bell's (1970) observational study of individual differences in attachment is described below.

Strange Situation Procedure

The security of attachment in one- to two-year-olds was investigated by Ainsworth and Bell (1970) in the 'strange situation' study, in order to determine the nature of attachment behaviors and styles of attachment.

Ainsworth (1970) developed an experimental procedure in order to observe the variety of attachment forms exhibited between mothers and infants.

The experiment is set up in a small room with one way glass so the behavior of the infant can be observed covertly. Infants were aged between 12 and 18 months. The sample comprised about 100 middle class American families.

The procedure, known as the ‘Strange Situation’, was conducted by observing the behavior of the infant in a series of seven 3-minute episodes, as follows

(click on the image below):

(1) Parent and infant alone.

(2) Stranger joins parent and infant.

(3) Parent leaves infant and stranger alone.

(4) Parent returns and stranger leaves.

(5) Parent leaves; infant left completely alone.

(6) Stranger returns.

(7) Parent returns and stranger leaves.

Four categories of behaviors are measured and observed: (1) separation anxiety: the unease the infant shows when left by the caregiver, (2) the infant’s willingness to explore, (3) stranger anxiety: the infant’s response to the presence of a stranger, and (4) reunion behavior: the way the caregiver was greeted on return. The observer notes down the behavior displayed and scores the behavior for intensity on a scale of 1 to 7.

Results - Attachment Styles

Ainsworth (1970) identified three main attachment styles, secure, insecure avoidant and insecure ambivalent. She concluded that these attachment styles were the result of early interactions with the mother. A forth attachment style known as disorganized was later identified (Main, & Solomon, 1990).

 Secure AttachmentAmbivalent AttachmentAvoidant Attachment
Separation AnxietyDistressed when mother leaves.Infant shows signs of intense distress when mother leaves.Infant shows no sign of distress when mother leaves.
Stranger AnxietyAvoidant of stranger when alone but friendly when mother present.Infant avoids the stranger - shows fear of stranger.Infant is okay with the stranger and plays normally when stranger is present.
Reunion behaviorPositive and happy when mother returns.Child approaches mother but resists contact, may even push her away.Infant shows little interest when mother returns.
OtherWill use the mother as a safe base to explore their environment.Infant cries more and explores less than the other 2 types.Mother and stranger are able to comfort the infant equally well.
% of infants701515

Secure Attachment

Securely attached children comprised the majority of the sample in Ainsworth’s (1970) study.

Such children feel confident that the attachment figure will be available to meet their needs. They use the attachment figure as a safe base to explore the environment and seek the attachment figure in times of distress (Main, & Cassidy, 1988).

Securely attached infants are easily soothed by the attachment figure when upset. Infants develop a secure attachment when the caregiver is sensitive to their signals, and responds appropriately to their needs.

According to Bowlby (1980) an individual who has experienced a secure attachment 'is likely to possess a representational model of attachment figures(s) as being available, responsive, and helpful' (Bowlby, 1980, p. 242).

Insecure Avoidant

Insecure avoidant children do not orientate to their attachment figure while investigating the environment.

They are very independent of the attachment figure both physically and emotionally (Behrens, Hesse, & Main, 2007).

They do not seek contract with the attachment figure when distressed. Such children are likely to have a caregiver who is insensitive and rejecting of their needs (Ainsworth, 1979). The attachment figure may withdraw from helping during difficult tasks (Stevenson-Hinde, & Verschueren, 2002) and is often unavailable during times of emotional distress.

Insecure Ambivalent / Resistant

The third attachment style identified by Ainsworth (1970) was insecure ambivalent (also called insecure resistant).

Here children adopt an ambivalent behavioral style towards the attachment figure. The child will commonly exhibit clingy and dependent behavior, but will be rejecting of the attachment figure when they engage in interaction.

The child fails to develop any feelings of security from the attachment figure. Accordingly they exhibit difficulty moving away from the attachment figure to explore novel surroundings. When distressed they are difficult to soothe and are not comforted by interaction with the attachment figure. This behavior results from an inconsistent level of response to their needs from the primary caregiver.

Strange Situation Conclusion

Ainsworth & Bell (1971) suggested that behavior in the strange situation classification was determined by the behavior of the primary carer (in this case the mother).

For example, securely attached infant are associated with sensitive & responsive primary care.

Insecure ambivalent attached infants are associated with inconsistent primary care. Sometimes the child’s needs and met and sometime they are ignored by the mother / father.

Insecure avoidant infants are associated with unresponsive primary care. The child comes to believe that communication of needs has no influence on the mother / father.

Ainsworth’s (1970) findings provided the first empirical evidence for Bowlby’s attachment theory .

For example, securely attached children develop a positive working model of themselves and have mental representations of others as being helpful while viewing themselves as worthy of respect (Jacobsen, & Hoffman, 1997).

Avoidant children think themselves unworthy and unacceptable, caused by a rejecting primary caregiver (Larose, & Bernier, 2001).

Ambivalent children have negative self image and exaggerate their emotional responses as a way to gain attention (Kobak et al., 1993).  Accordingly, insecure attachment styles are associated with an increased risk of social and emotional behavioral problems via the internal working model.

Evaluation of The Strange Situation

The strange situation classification has been found to have good reliability.  This means that it achieves consistent results.  For example, a study conducted in Germany found 78% of the children were classified in the same way at ages 1 and 6 years (Wartner et al. 1994).

Although, as Melhuish (1993) suggests, the Strange Situation is the most widely used method for assessing infant attachment to a caregiver, Lamb et al. (1985) have criticized it for being highly artificial and therefore lacking ecological validity. The child is placed in a strange and artificial environment, and the procedure of the mother and stranger entering and leaving the room follows a predetermined script.

Mary Ainsworth's conclusion that the strange situation can be used to identify the child's type of attachment has been criticized on the grounds that it identifies only the type of attachment to the mother. The child may have a different type of attachment to the father or grandmother, for example (Lamb, 1977). This means that it lacks validity, as it is not measuring a general attachment style, but instead an attachment style specific to the mother.

In addition, some research has shown that the same child may show different attachment behaviors on different occasions. Children's attachments may change, perhaps because of changes in the child's circumstances, so a securely attached child may appear insecurely attached if the mother becomes ill or the family circumstances change.

The strange situation has also been criticized on ethical grounds. Because the child is put under stress (separation and stranger anxiety), the study has broken the ethical guideline protection of participants.

However, in its defence the separation episodes were curtailed prematurely if the child became too stressed. Also, according to Marrone (1998), although the Strange Situation has been criticized for being stressful, it is simulating everyday experiences, as mothers do leave their babies for brief periods of time in different settings and often with unfamiliar people such as baby sitters.

Finally, the studies sample is biased - comprising 100 middle class American families. Therefore, it is difficult to generalize the findings outside of America and to working class families.


Ainsworth, M. D. S. (1967). Infancy in Uganda: Infant care and the growth of love.

Ainsworth, M. D. S., & Bell, S. M. (1970). Attachment, exploration, and separation: Illustrated by the behavior of one-year-olds in a strange situation. Child Development, 41, 49-67.

Ainsworth, M. D., Bell, S. M., & Stayton, D. J. (1971). Individual differences in strange-situation behaviour of one-year-olds.

Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale, NJ: Erlbaum.

Ainsworth, M. D. S. & Wittig, B. A. (1969). Attachment and exploratory behavior of one-year-olds in a strange situation. In B. M. Foss(Ed. ),Determinants of infant behavior(Vol. 4,pp. 111-136). London: Methuen.

Behrens, K. Y., Hesse, E., & Main, M. (2007). Mothers' attachment status as determined by the Adult Attachment Interview predicts their 6-year-olds' reunion responses: A study conducted in Japan. Developmental Psychology, 43(6), 1553.

Bowlby, J. (1969). Attachment. Attachment and Loss: Vol. 1. Loss. New York: Basic Books.

Jacobsen, T. & Hoffman, V. (1997). Children’s attachment representations: Longitudinal relations to school behavior and academic competency in middle childhood and adolescence. Developmental Psychology, 33, 703-710.

Kobak, R. R., Cole, H. E., Ferenz-Gillies, R., Flemming, W. S., & Gamble, W. (1993). Attachment and emotional regulation during mother-teen problem-solving. A control theory analysis. Child Development, 64, 231-245.

Lamb, M. E. (1977). The development of mother-infant and father-infant attachments in the second year of life. Developmental Psychology, 13, 637-48.

Larose, S., & Bernier, A. (2001). Social support processes: Mediators of attachment state of mind and adjustment in later late adolescence. Attachment and Human Development, 3, 96-120.

Main, M., & Solomon, J. (1990). "Procedures for identifying infants as disorganized/disoriented during the Ainsworth Strange Situation". M.T. Greenberg, D. Cicchetti & E.M. Cummings (Eds.), Attachment in the Preschool Years (pp. 121–160). Chicago, University of Chicago Press.

Marrone, M. (1998). Attachment and interaction. Jessica Kingsley Publishers.

Melhuish, E. C. (1993). A measure of love? An overview of the assessment of attachment. ACPP Review & Newsletter, 15, 269-275.

Schaffer, H. R., & Emerson, P. E. (1964) ‘The Development of Social Attachments in Infancy’. Monographs of the Society for Research in Child Development, 29 (3), serial number 94.

Stevenson-Hinde, J., & Verschueren, K. (2002). Attachment in childhood. status: published.

Thompson, R. A., Gardner, W., & Charnov, E. L. (1985). Infant-mother attachment: The origins and developmental significance of individual differences in Strange Situation behavior. LEA.

Wartner, U. G., Grossman, K., Fremmer-Bombik, I., & Guess, G. L. (1994). Attachment patterns in south Germany. Child Development, 65, pp. 1014-27.

How to cite this article:

McLeod, S. A. (2008). Mary Ainsworth. Retrieved from

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